The retrovirus HIV (human immunodeficiency virus) has been identified as the causative agent in acquired immunodeficiency syndrome (AIDS). Infection is followed in many cases by a clinically quiescent or latent phase that appears to continue as long as host antiviral defense is intact. These findings raise the possibility htat host susceptibility factors (i.e., "environmental cofactors") may influence the progression of the disease. The identification of such cofactors is, obviously, of immense significance in the understanding and characterization of the pathogenesis of AIDS. An estimated 25% of all AIDS cases in the United States are drug abusers. Recently, the findings that various "drugs of abuse" (i.e., opiates) are immunomodulatory and immunocompromising has ld to the suggestion that opiates may serve as putative environmntal cofactors and influence the susceptibility and progression of HIV infection. Our goal is to define the relationship between opiates and the human immunodeficiency virus genome on a functional level. We will use molecular genetic approaches and both in vitro and in vivomodels to characterize the effects of opiates on the transcriptional regulation of HIV. To examine this question directly, we will use HIV-long terminal repeat-chloramphenicol acetyltransferase fusion genes (HIV/LTR-CAT). The HIV/LTR-CAT chimeric constructs will be transfected into both human clonal T-cells and human neural cells in order to establish appropriate in vitro models in which to examine this putative relationship. W have demonstrated that obth cell types are responsive to morphine in a naloxone-reversible manner at the level of gene expression. We will use deletion mutagenesis to define the opiate-responsive region of the HIV LTR. Since previous results from our laboratory have demonstrated a rapid and transient inductive effect of morphine on c-fos expression, we will also determine if Fos can function as an adaptor gene and link the short-term post-receptor effects of opiates to the activation HIV expression. Our hypothesis is based on the recent identification of two AP-1 transcriptional regulatory sequences within the HIV LTR and that the AP-1 sequence is required for the transcriptional activation of eukaryotic genes by a Fos-containing nucleoprotein complex. Finally, we have proposed to introduce HIV/LTR-CAT fusion genes into the germline of mice (i.e., transgenic mice) in order to establish appropriate in vivo models. We predict our findings will have important implications for the pathogenesis of AIDS in patients classified as drug abusers.